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LEVI STOCKBRIDGE 

and the 

Stockbridge Principle of Plant Feeding 

By WILLIAM H. BOWKER 



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LEVI STOCKBRIDGE 

and the 

Stockbridge Principle 
of Plant Feeding 



With 
Compliments of the Author. 



Extract from Tribute 
By WILLIAM H. BOWKER 

Read at the 

Memorial Exercises at Amherst 

1904 



Printed 
BOSTON 1911 



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LEVI STOCKBRIDGE 

Professor <>i AKriculture in the Massachusetts Agricultural College from 1871 
to 1882. and President of the Collese from 18.S0 to 1S82. 

1820—1904 



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^' ' BIOGRAPHICAL NOTE 



LEVI STOCKBRIDGE 



Biographical Note: Levi Stockbridge, a man of the 
type of Abraham Lincoln, was a farmer's son and 
for many years a practical farmer in Hadley, Mass. 
Except for such schooling as he received at the 
district school, and a few lectures in chemistry 
which he attended at Amherst College, he was 
self-taught. He possessed an alert mind, a reten- 
tive memory, and a marked talent for clear, 
forceful expression. Becoming distinguished as 
a leader and public speaker, he was sent for sev- 
eral terms to both branches of the Massachusetts 
Legislature. He was Massachusetts' first cattle 
commissioner, and in the course of his twenty- 
seven years' continuous service in that office he 
came to know nearly every farmer in the state, 
who looked up to and respected him. One of his 
greatest achievements was the quick and effective 
manner in which he stamped out a threatened 
epidemic of pleuro-pneumonia. 

He. was instrumental in securing for the state 
the Agricultural College located at Amherst, 
Mass., in spite of ridicule and strong opposition. 
He was its first farm superintendent; later, pro- 
fessor of agriculture, and for two years its presi- 
dent. During his connection with the college, at 
considerable personal inconvenience, he frequently 
endorsed the notes of the college to the local 
banks, thus tiding it over financial stress. He 



BIOGRAPHICAL NOTE 



was also " an ever-present help in time of need " 
to many worthy students. All the students were 
" his boys," and to all he was counselor and 
friend, and endearingly known as " Prof Stock." 

Physically, he was tall and wiry, with a great 
capacity for work, which he never shirked. He 
was humorous, tactful, judicial, but outspoken; 
always sunny, hopeful, sane; of the right makeup 
to lead and teach young manhood. He sprang 
from the plain people and belieVed in them; thus 
he naturally abhorred a plutocracy and believed 
in every man's having a fair chance. 

It is thought that he did as much to advance 
the cause of agricultural education and to popu- 
larize the chemistry of plant foods as any one man 
of his time. It was while he occupied the chair 
of professor of agriculture that he evolved the 
Stockbridge principle of plant feeding and the 
Stockbridge formulas which he freely published 
to the world, and which have made his name a 
household word in rural communities. 



THE STOCKBRIDGE PRINCIPLE 
OF PLANT FEEDING 



If I were asked what was Professor Stock- 
bridge's greatest contribution to agriculture, I 
should say that it was not his formulas for crop 
feeding by which he is so widely known; for, 
useful as these were, they were but stepping 
stones to a better knowledge of the object and 
use of fertilizers. His greatest contribution to 
agriculture, as it seems to me, was his new con- 
ception of the office of fertility in farm economy. 
Up to the time of the publication of the Stock- 
bridge formulas, the practice had been to manure 
the soil in order to restore lost fertility and to 
supply deficiencies in the soil, as ascertained by 
a chemical or crop analysis of the soil. Stock- 
bridge saw that this method was not a practical 
solution of the problem, for neither chemical 
nor crop analysis of the soil could be relied upon 
as a true guide to its enrichment. The chemist 
disclosed too much that was misleading and the 
crop too little that was conclusive. But, what 
is more to the point, Stockbridge saw that we 
had taken hold of the problem at the wrong end. 

A PRACTICAL SOLUTION 

It was not the soil, hut the crop, that we should 
first consider. We should study it and its needs, 
and supply it, as far as we were able, with the 
necessary elements of plant nutrition by the 



FEED THE PLANT— NOT THE SOIL 



use of properly balanced manures. In a word, 
he turned from the inert soil, which could not 
answer, to the living crop, which could, and put 
this question to it: 

" What shall I supply you in excess of what 
you may obtain from the soil or air by your own 
habits and conditions of growth to make you 
a perfect and profitable crop? " 

On the other hand, the farmer was asking him: 

" What shall I use to produce profitable crops 
— how" much and in what form? " 

Starting, then, from the crop, with the farm- 
er's question ever spurring him on, and with 
such data as he could find, he worked out his 
well-known formulas, which were published 
broadcast in 1876. And let me say here that 
besides being published in many agricultural 
papers and reports, more than half a million 
pamphlets containing them were distributed. 

FORMULAS NOT INFALLIBLE 

He did not claim that his formulas were 
infallible, for he anticipated and announced, 
what we soon discovered in practice, that they 
would need to be modified, as experience should 
point the way. They served, however, a greater 
purpose even than Stockbridge dreamed at the 
time — they centered our thought and our 
study on the crop. From that time on we dis- 
cussed plant food and not soil food — plant feed- 
ing instead of soil manuring. *' Feed the crop 
rather than the soil " was a frequent expression 
at that time. 

It is well to observe here that crop formulas 
were not new. Ville and others had published 



THE FIRST DEFINITE METHOD 



various sets. The Stockbridge formulas, how- 
ever, were unique in this: that they were based 
not alone on the analysis of the crop, but on 
its power of absorption from all the sources of 
fertility — from soil, air, and water. Thus 
Stockbridge boldly prescribed: 

" To produce fifty bushels of shelled corn per 
acre (without any stable manure) and its natural 
proportion of stover, more than the natural 
yield of the land, apply so many pounds each of 
nitrogen, potash, and phosphoric acid. Or, to 
produce a stated quantity of tobacco leaf of 
the desired color and texture, apply a stated 
quantity of plant food elements, preferably in 
the form of sulphates and nitrates." 

Here, then, for the first time, a definite way was 
prescribed to attain a definite object. It was a 
startling proposition, and, as might be expected, 
it brought ridicule from many quarters, but 
Stockbridge did not allow that to disturb him. 
He knew that the commercial farmer needed a 
tangible starting point. He knew that to con- 
sider the needs of the crop, the living thing, both 
as to amount and kind of plant food, rather than 
the needs of the soil, an unknown and unknow- 
able quantity, was not only a common-sense way 
of meeting the problem of plant nutrition, but 
a very direct way of helping the farmer out of 
the quagmire of doubt. 

INSURE THE CROP 

The formulas might not be accurate; in some 
cases they might supply excessive amounts of 
plant food elements and apparently be very 
wasteful, yet he believed that in the end it was 



STUDY THE PLANT 



better economy to apply too much and insure a 
crop than use too little and lose a crop. Never- 
theless, as Professor Stockbridge anticipated 
would be the case, the fertilizers based on his 
formulas were modified from time to time as we 
gained light, chiefly by the reduction of nitrogen 
and the increase of phosphoric acid, as it was 
found that many crops were able to gather 
from natural sources, through bacterial action or 
otherwise, some part of the required nitrogen, 
and that an excess of available phosphoric acid 
would hasten maturity. It was also found that 
to supply the full complement of nitrogen in 
addition to what the crop would assimilate for 
itself tended in many cases to produce an un- 
balanced growth; yet, on the other hand, it 
was found that in some cases, especially where 
a forced growth or a tender leaf was required, 
an excess of nitrogen was desirable. Thus it 
will be seen that the crop was both the starting 
and the objective point. Not only its chemical 
needs, but its habits and conditions of growth, 
the object for which it was grown, and its 
market qualities, were all factors which influ- 
enced the composition or modification of the 
fertilizers; and the same factors are as potent 
to-day. Thus, since it was the crop that chiefly 
concerned Professor Stockbridge, how natural 
and sensible was his question: " What shall I 
supply you to make you a perfect and profitable 
crop? " 

POTENTIAL FERTILITY 

Let us now consider for a moment another 
phase of the subject, namely, the potential 



THE PLANT FOOD IN THE SOIL 



fertility of the soil, or " the natural yield," to 
which Professor Stockbridge frequently referred. 
It has been known for a long time that practically 
all tillable soils are rich in plant food elements, 
and yet many of them are barren, and most of 
them will not produce profitable crops without 
the aid of manure or fertilizer. 

Prof. Frederick D. Chester, of Delaware, states 
in an able bulletin recently published: 

" An average of the results of 49 analyses of the typi- 
cal soils of the United States showed per acre for the 
first eight inches of surface 2,600 pounds of nitrogen, 
4,800 pounds of phosphoric acid, and 13,400 pounds of 
potash. The average yield of wheat in the United States 
is 14 bushels per acre. Such a crop will remove 29.7 
pounds of nitrogen, 9.5 pounds of phosphoric acid, 13.7 
pounds of potash. 

" Now, if all the potential nitrogen, phosphoric acid, 
and potash could be rendered available, there is present 
in such an average soil, in the first eight inches, enough 
nitrogen to last ninety years, enough phosphoric acid 
for five hundred years, and enough potash for one 
thousand years." 

In a word, potential fertility represents plant 
food which is so tightly locked up that it is not 
available for present needs and becomes avail- 
able only through the process of decay and 
disintegration, which is too slow to meet the 
requirements of the commercial farmer. Stock- 
bridge realized the situation, but instead of 
asking the soil how much of the potential fer- 
tility could be depended upon for each crop (a 
question which will never be satisfactorily 
answered), he went to the crop and asked it how 



THE VERY SMALL AMOUNT REQUIRED 



much it was necessary to supply for a stated 
yield over and above the natural yield of the 
land. In all cases he found it to be a very small 
quantit}^ For the corn crop, not over 200 
pounds of nitrogen, potash, and phosphoric acid 
was necessary, which the crop would return 
fiftyfold (at least five tons in stalk and grain), 
so little to produce so much, and yet, if this little 
quantity of 200 pounds was not supplied, the 
crop would be a failure. 

THE LITTLE ESSENTIAL BALANCE 

It w^as this little essential balance of available 
plant food which stood between success and 
failure that concerned Professor Stockbridge, as 
it concerns every farmer to-day. Although it 
was small, he did not deem it wise to depend 
upon the potential fertility of the soil to supply 
it, or even any considerable part of it. For the 
commercial farmer it was too risky and uncertain. 
To insure a crop, as far as one was able, was a 
cardinal principle with him; not to do it was, in 
his eyes, almost a crime. But he felt that all 
these things would right themselves as we came 
to know more about farm crops and their 
environment. 

THE SINGLE ELEMENT DOCTRINE 

As bearing on the economy of his system of 
plant feeding, I want to quote here one of his 
apt illustrations. He said in effect: 

" In a sense the farmer is a manufacturer and the soil 
is his machine, into which he puts plant food, and out 
of which, by the aid of nature and his own efforts, he 



THE SINGLE ELEMENT DOCTRINE 



takes his product at harvest time. If the soil machine 
is a good one, so much the better. If it has a balance of 
crop-producing power to its credit, let us preserve that 
balance for an emergency. Let us not draw on it for 
present needs." 

He had no patience with the so-called single- 
element doctrine, which depends for its success 
on the potential fertility — no patience with the 
farmer who was trying to find out for himself if 
he could leave out any one of the three leading 
elements of plant nutrition (nitrogen, potash, 
and phosphoric acid), or how little of each he 
could get along with. That was a proper subject 
for the scientific worker to investigate, but until 
we knew more about it, the practical farmer, who 
had his living to make and bills to pay, should 
not tinker with it. To Stockbridge it meant, in 
the end, improvident farming. At best, the 
farmer had to take great chances, especially with 
the weather, — the largest factor in crop raising, 
over which he had no control, — but he should 
take no chances with the things which he could 
control. Among these were the amount and 
kind of manure which he applied to his crops. 
Thus, if he hoped for a stated crop he should at 
least fertilize intelligently for that crop. For 
the man who was dependent on his crops any 
other course was unwise. Moreover, any other 
course would leave the soil machine in a poorer 
condition than he found it. Broadly speaking, 
to encourage him to take out more than he 
put back was not only bad economy, but bad 
morals, and should be discouraged, for in the 
end it would lead to crop bankruptcy. 



DIFFERENT FORMS OF PLANT' FOOD 



RAISING THE STANDARD 

It is needless to say that the farmers appreci- 
ated this bold course. As Stockbridge put it, 
they jumped on his wagon before he was ready 
to start. He was indeed their prophet, who led 
them out of the wilderness of speculation into 
the light of practical methods. As might be 
expected, this new conception of the use of 
chemical manures — or plant food, as he liked 
to call it — not only revolutionized all our 
notions of fertilization, but the entire fertilizer 
business as well. It immediately raised the 
standard of commercial manures from ordinary 
superphosphates, containing no potash, to 
" complete manures," many of them rich in 
potash. Special fertilizers for special crops or 
classes of crops were brought out by various 
makers, and the business received a new impetus 
and a new recognition in the community. It 
was put on a sound footing, from which it can 
never be displaced. 

STOCK FEEDING AND PLANT FEEDING 

As in stock feeding we chiefly concern our- 
selves with the study of the animal and its needs, 
so in plant feeding we must make an intelligent 
study of tJie needs of the living crop. As we know 
how to feed the cow for milk or beef, so we must 
know how to feed the plant for leaf or seed. 
Not only must we know the amount of plant 
food to be supplied, based on crop requirements, 
but the form and association of the different 
elements must be considered; and in the study 
of this problem we must also continue to study 
the soil, its potential fertility, its physical and 



10 



CONTINUAL STUDY NEEDED 



chemical characteristics, and particularly the 
lower orders of life which it contains, the bacteria 
and other unseen forces. In short, we must 
continue our study of all the sources and forces 
of fertility, to the end that we may know what 
each contributes to the upbuilding, not neces- 
sarily of the soil, but of the crop life above the 
soil. Thus did Stockbridge teach and practice. 

GOOD PRACTICE AND GOOD SCIENCE 

As Stephenson made practical the discovery of 
Watts, as Singer improved upon the invention 
of Howe, so Stockbridge took the teachings of 
Liebig and Johnson, the tables of Wolf, and the 
experiments of Goessmann, Atwater, and Sturte- 
vant, and applied them to practical and useful 
ends. While the system of plant feeding which 
he employed, or perhaps I should say, the 
method of application as prescribed in his 
formulas, did not appeal to the scientific mind 
in the beginning, it did appeal to the practical 
farmers, for it met their needs as no other 
method ever before had done. As good practice 
and good science must agree in the end, so I 
believe the scientific world is coming to agree 
with the practical farmer that the system and 
the method of application for which Stockbridge 
stood and labored is as truly scientific as it is 
thoroughly practical, and to accord him a high 
place among the workers for the advancement of 
scientific as well as practical husbandry. 



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